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This module implements some useful functions on pathnames. To read or
write files see open(), and for accessing the filesystem see the
os module.

Note

On Windows, many of these functions do not properly support UNC pathnames.
splitunc() and ismount() do handle them correctly.

Unlike a unix shell, Python does not do any automatic path expansions.
Functions such as expanduser() and expandvars() can be invoked
explicitly when an application desires shell-like path expansion. (See also
the glob module.)

Note

Since different operating systems have different path name conventions, there
are several versions of this module in the standard library. The
os.path module is always the path module suitable for the operating
system Python is running on, and therefore usable for local paths. However,
you can also import and use the individual modules if you want to manipulate
a path that is always in one of the different formats. They all have the
same interface:

Return the base name of pathname path. This is the second element of the
pair returned by passing path to the function split(). Note that
the result of this function is different
from the Unix basename program; where basename for
'/foo/bar/' returns 'bar', the basename() function returns an
empty string ('').

Return the longest path prefix (taken character-by-character) that is a prefix
of all paths in list. If list is empty, return the empty string ('').
Note that this may return invalid paths because it works a character at a time.

Return True if path refers to an existing path. Returns False for
broken symbolic links. On some platforms, this function may return False if
permission is not granted to execute os.stat() on the requested file, even
if the path physically exists.

On Unix and Windows, return the argument with an initial component of ~ or
~user replaced by that user‘s home directory.

On Unix, an initial ~ is replaced by the environment variable HOME
if it is set; otherwise the current user’s home directory is looked up in the
password directory through the built-in module pwd. An initial ~user
is looked up directly in the password directory.

On Windows, HOME and USERPROFILE will be used if set,
otherwise a combination of HOMEPATH and HOMEDRIVE will be
used. An initial ~user is handled by stripping the last directory component
from the created user path derived above.

If the expansion fails or if the path does not begin with a tilde, the path is
returned unchanged.

Return the argument with environment variables expanded. Substrings of the form
$name or ${name} are replaced by the value of environment variable
name. Malformed variable names and references to non-existing variables are
left unchanged.

On Windows, %name% expansions are supported in addition to $name and
${name}.

Return the time of last modification of path. The return value is a number
giving the number of seconds since the epoch (see the time module).
Raise os.error if the file does not exist or is inaccessible.

Return the system’s ctime which, on some systems (like Unix) is the time of the
last metadata change, and, on others (like Windows), is the creation time for path.
The return value is a number giving the number of seconds since the epoch (see
the time module). Raise os.error if the file does not exist or
is inaccessible.

Return True if pathname path is a mount point: a point in a file
system where a different file system has been mounted. The function checks
whether path‘s parent, path/.., is on a different device than path,
or whether path/.. and path point to the same i-node on the same
device — this should detect mount points for all Unix and POSIX variants.

Join one or more path components intelligently. The return value is the
concatenation of path and any members of *paths with exactly one
directory separator (os.sep) following each non-empty part except the
last, meaning that the result will only end in a separator if the last
part is empty. If a component is an absolute path, all previous
components are thrown away and joining continues from the absolute path
component.

On Windows, the drive letter is not reset when an absolute path component
(e.g., r'\foo') is encountered. If a component contains a drive
letter, all previous components are thrown away and the drive letter is
reset. Note that since there is a current directory for each drive,
os.path.join("c:","foo") represents a path relative to the current
directory on drive C: (c:foo), not c:\foo.

Normalize the case of a pathname. On Unix and Mac OS X, this returns the
path unchanged; on case-insensitive filesystems, it converts the path to
lowercase. On Windows, it also converts forward slashes to backward slashes.

Normalize a pathname by collapsing redundant separators and up-level
references so that A//B, A/B/, A/./B and A/foo/../B all
become A/B. This string manipulation may change the meaning of a path
that contains symbolic links. On Windows, it converts forward slashes to
backward slashes. To normalize case, use normcase().

Return a relative filepath to path either from the current directory or
from an optional start directory. This is a path computation: the
filesystem is not accessed to confirm the existence or nature of path or
start.

Split the pathname path into a pair, (head,tail) where tail is the
last pathname component and head is everything leading up to that. The
tail part will never contain a slash; if path ends in a slash, tail
will be empty. If there is no slash in path, head will be empty. If
path is empty, both head and tail are empty. Trailing slashes are
stripped from head unless it is the root (one or more slashes only). In
all cases, join(head,tail) returns a path to the same location as path
(but the strings may differ). Also see the functions dirname() and
basename().

Split the pathname path into a pair (drive,tail) where drive is either
a drive specification or the empty string. On systems which do not use drive
specifications, drive will always be the empty string. In all cases, drive+tail will be the same as path.

Split the pathname path into a pair (root,ext) such that root+ext==path, and ext is empty or begins with a period and contains at most one
period. Leading periods on the basename are ignored; splitext('.cshrc')
returns ('.cshrc','').

Changed in version 2.6: Earlier versions could produce an empty root when the only period was the
first character.

Split the pathname path into a pair (unc,rest) so that unc is the UNC
mount point (such as r'\\host\mount'), if present, and rest the rest of
the path (such as r'\path\file.ext'). For paths containing drive letters,
unc will always be the empty string.

Calls the function visit with arguments (arg,dirname,names) for each
directory in the directory tree rooted at path (including path itself, if it
is a directory). The argument dirname specifies the visited directory, the
argument names lists the files in the directory (gotten from
os.listdir(dirname)). The visit function may modify names to influence
the set of directories visited below dirname, e.g. to avoid visiting certain
parts of the tree. (The object referred to by names must be modified in
place, using del or slice assignment.)

Note

Symbolic links to directories are not treated as subdirectories, and that
walk() therefore will not visit them. To visit linked directories you must
identify them with os.path.islink(file) and os.path.isdir(file), and
invoke walk() as necessary.

Note

This function is deprecated and has been removed in Python 3 in favor of
os.walk().